Merry Christmas to all those who are celebrating today!
I have to admit, I have some ambivalence about wishing my Christian friends joy on this holiday. I don't believe in the Trinity; indeed I think the doctrine is basically a mistaken interpretation of Jesus's teachings and life, and it seems a bit odd to offer felicitations to people for what I believe is essentially an error.
That is mitigated a bit by the fact that I believe Jesus is a prophet, and thus a celebration of his birth is a celebration of God's engagement with the world; but I don't celebrate the births of any other prophet, so it seems out of proportion.
At the same time, I full-heartedly embrace the message of Christ -- that God is infinitely merciful, that He/She/It loves this creation and everything in it without reserve, and actively expresses that mercy, love, and forgiveness in this world. Whether it is the compassion of the Boddhisattva who delays his or her own nirvana to help other souls along the path to enlightenment, the sacrifice of Christ to atone for humanity's sins, or the guidance Allah offers in the Qur'an and the promise of ever extended mercy, love, provision and forgiveness from him, the idea that God is not just the creator, that he did not just set the process of creation in motion with the Big Bang and then abandon the world, but remains actively engaged in this world, in helping humanity overcome our baser instincts is present in many religions. I don't think this is without reason. We may not always understand how God works, but I believe God does, and does so with love and mercy for all.
When I look around me, I see ample evidence of God's love. The heart-stopping beauty of the natural world, the love that flows between people, the impulse to goodness we all feel. If one believes in God, it seems impossible to believe in a God that is anything less that a artist who is fully in love with his/her/its work of art.